1. Field of the Invention:
This invention relates to bowling pins formed of plastic.
2. Description of Related Art:
Short supply of suitable woods make important the development of plastic bowling pins, whose performance in competition must be equivalent to approved wood pins.
Experimental bowling pins have been made with plastic shells over wood or foam cores. Such pins have experienced serious problems of separation of the shell from the core. There have been some attempts, as in U.S. Pat. No. 3,971,837 to Hasegawa, to solve this problem by forming grooves in the exterior surface of the core, and casting the plastic shell thereabout to fill and hold to the grooves.
Plastic base rings have been customarily used on wood pins to avoid excessive sliding on the lane. Hasegawa used three pre-formed plastic base rings on a composite pin, but Hasegawa does not teach any method to prevent the separation of the ring from the composite pin.
Wood pins have an added disadvantage in that once a pin is damaged it cannot be refurbished for use. A composite pin which can be refurbished is highly desirable.